Rectifying diodes, which are key elements that support present-day electronics, are fabricated from a silicon semiconductor, gallium arsenide semiconductor, or such. Rectifying diodes typically possess two resistance values in the forward bias direction and the reverse bias direction, using the p-n junction.
Meanwhile, there is a known technique that provides rectifying function within the voltage range of about −5 V to +5 V by placing two Pt electrodes on the surface of a rutile-type TiO2 single crystal, and applying a large electric power of 75 V/180 s between the electrodes (see Non-patent Document 1).
Furthermore, resistance switching devices that are capable of non-volatile memorization of low and high resistance states by placing two-terminal ohmic electrodes on a single crystal of Ti4O7 or such having a rutile-type crystal structure, and applying two threshold voltages, have been disclosed (see Patent Document 1).    [Patent Document 1] Japanese Patent Application Kokai Publication No. (JP-A) 2006-86310 (unexamined, published Japanese patent application)    [Non-patent Document 1] Applied Physics Letters, Vol. 91, 112101 (2007), pages 112101-1 to 112101-3